In the prior art, it is known to implement a filter module constituted by a metal casing fitted at each end with a support plate arranged to present one or more passages for enabling filter elements of tubular shape to be positioned relative to one another. The filter elements thus extend inside the outer casing, parallel to one another, and they are mounted in leaktight manner at each end to a support plate.
Each filter element is constituted by a porous support having formed therein one or more channels of inside surface provided with at least separator layer of nature and morphology that are adapted to separate out molecules or particles contained in the liquid medium flowing inside the channels. Such a filter element uses a sieve effect to separate out molecular or particulate species insofar as all molecules or particles larger than the diameter of the pores in the separator layer are stopped. Filter elements perform cross-flow filtering of the fluid medium in order to obtain at the peripheral surface of the filter elements the filtrate or permeate that is for recovery in a collection volume situated between the casing and the support plates. The casing is provided in association with each support plate with an outlet passage for the permeate, which passage is suitable for connection to a recovery circuit.
In order to provide sealing between the end portions of the filter elements and the support plates, sealing gaskets are put into position and clamped by means of a metal backing plate fixed against each support plate and enabling the filter module to be connected to a loop in which the fluid medium for treatment circulates.
In certain applications of the food industry type, for example, the need arises to ensure that the filter module does not present any zone in which a liquid can stagnate. Stagnating liquid is liable to lead to proliferation of bacteria that is prejudicial to the use of such filter modules for food purposes.